How to render multiple scenes in succession from the timeline?
For rendering more Scenes created in one blend file use Video Sequencer (called VSE).
Scene_Cube

Scene_Sphere

Create a third New scene, switch to Video Editing layout and  with mouse hovering above Video Sequencer editor Add Shift+A Scene strips and organised on Timeline as needed.

From Video Sequencer properties panel N (with Scene strip selected in timeline) under Strip &gt; Scene &gt; Camera you can choose what camera object should be used (if you have more than one in that scene).
Or you can also use one camera in Scene_Cube linked to Scene_Sphere.